Lithography apparatus having dual reticle edge masking assemblies and method of use

ABSTRACT

A lithography apparatus includes at least two reticle edge masking assemblies (REMAs). The lithography apparatus further includes a light source configured to emit a light beam having a wavelength and a beam separating element configured to divide the light beam into more than one collimated light beam. Each REMA is positioned to receive one of the more than one collimating light beams and each REMA comprises a movable slit for passing the one collimated light beam therethrough. The lithography apparatus further includes at least one mask having a pattern, where the at least one mask is configured to receive light from at least one of the REMA and a projection lens configured to receive light from the at least one mask. A method of using a lithography apparatus is also discussed.

BACKGROUND

As technology nodes decrease, the density of features on a substrateincreases. The decreased spacing between features on the substrate canresult in the separation of a layout design into multiple patterns dueto resolution constraints. A conventional lithographic arrangement,including a single reticle edge masking assembly, is only capable oftransferring one pattern at a time.

The reticle edge masking assembly includes a slit extending acrosssubstantially the entire width of the reticle masking element. The slitcan translate along a length direction, perpendicular to the width ofthe reticle masking element. The translation of the slit sequentiallyilluminates portions of a mask whose pattern is transferred to a wafer.During a patterning process, the wafer moves in a direction opposite tothe direction of translation of the slit.

Often a pattern is repeated many times on a single wafer. Each time apattern is repeated the slit is reset to an original position, or thedirection of wafer movement is reversed. To maximize throughput themovement direction of the wafer is often reversed. However, thisarrangement causes particles to build up on a surface of the wafer. Thebuild up of particles can block illumination passing through the reticlemasking element, resulting in an error in the pattern transfer.

In order to transfer multiple patterns to the wafer, the mask in thelithographic arrangement is replaced for each pattern, or multiplelithographic arrangements are used with each having a separate pattern.The replacement of masks or the use of multiple lithographicarrangements increases production time and cost.

DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout. It is emphasized that, in accordance with standardpractice in the industry various features may not be drawn to scale andare used for illustration purposes only. In fact, the dimensions of thevarious features in the drawings may be arbitrarily increased or reducedfor clarity of discussion.

FIG. 1A is a diagram of a lithography apparatus having dual reticle edgemasking assemblies according to one or more embodiments;

FIG. 1B is a cross-sectional view of a REMA taken along line 1B-1B ofFIG. 1A.

FIG. 2 is a functional diagram of a lithography apparatus having dualreticle edge masking assemblies according to one or more embodiments;

FIG. 3 is a flow chart of a method of a patterning process according toone or more embodiments; and

FIG. 4 is a graph of velocity of a slit of a reticle edge maskingassembly versus time according to one or more embodiments; and

FIG. 5 is a diagram of a scanning path for a patterning processaccording to one or more embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are of course, merely examples and are notintended to be limiting.

FIG. 1A is a diagram of a lithography apparatus 100 having dual reticleedge masking assemblies (REMAs) 102 a and 102 b. Lithography apparatus100 includes a light source 104 emitting a light beam 105. A beamseparating element 106 receives the light beam 105 from light source 104and splits the light beam 105 into two collimated light beams 107 a and107 b. Two collimated light beams 107 a and 107 b are each incident on acorresponding REMA 102 a and 102 b. Light 109 a and 109 b passingthrough REMAs 102 a and 102 b contacts masks 108 a and 108 b,respectively. Masks 108 a and 108 b include patterns which blockportions of the incident light 109 a and 109 b. Light 111 a and 111 btransmitted by masks 108 a and 108 b is conducted by reflective elements110 a and 110 b, respectively, and light redirecting element 112 to aprojection lens 114. Projection lens 114 focuses the incident light 117onto a wafer 116 carried by a movable stage 118. A space 120 separates asurface of wafer 116 from projection lens 114. An immersion liquid 122substantially fills the space 120.

REMAs 102 a and 102 b each include a slit to allow light to pass throughonly a portion of the REMA. The slit is able to translate in a directionperpendicular to the incident light beam. The speed of the slit isadjustable and ranges from 400 mm/s to 700 mm/s. The speed of the slitin a specific application is selected based on a size of the slit, anintensity of the light beam and a material being patterned. In someembodiments, the speed of the slit is selected by a user. In someembodiments, the speed of the slit is calculated and controlled by aprocessor connected to lithography apparatus 100. Light incident 107 aand 107 b on portions of REMAs 102 a and 102 b other than the slit isblocked and does not propagate through the REMAs. In some embodiments,lithography apparatus 100 includes more than two REMAs.

The size of the REMAs 102 a and 102 b is sufficiently large to positionthe slit out of the incident light beam outside the incident light beams107 a and 107 b on either side of the incident light beam 107 a and 107b. When the slit is positioned outside the incident light beam, no lightpropagates through the REMA 102 a or 102 b. FIG. 1B is a cross-sectionalview of REMA 102 a taken along line 1B-1B of FIG. 1A. REMA 102 a issufficiently large to position a slit 150 a out of a path of incidentlight beam 107 a. Slit 150 a indicated by a solid outline is located ina first position outside incident light beam 107 a. During operation,slit 150 a moves from the first position to a second position indicatedby slit 150 b having a dashed outline along a movement direction 152. Insome embodiments, the relative location of the first position and thesecond position are reversed.

In some embodiments, light source 104 is a laser light source. In someembodiments, light source 104 is a lamp light source. In someembodiments, a wavelength of light 105 emitted by light source 104ranges from 13.5 nm to 365 nm. In some embodiments, the wavelength oflight 105 emitted by light source 104 is ultraviolet light, includingdeep ultraviolet light, extreme ultraviolet light or vacuum ultravioletlight. In some embodiments, light source 104 includes an i-line laser, aKrF laser, an ArF laser, an ArFi laser, or other suitable light source.

Beam separating element 106 receives the light beam 105 from lightsource 104 and emits two collimated beams 107 a and 107 b. Onecollimated beam 107 a and 107 b emitted by beam separating apparatus 106is incident on each REMA 102 a and 102 b. In some embodiments, beamseparating element 106 divides the light beam 105 into more than twocollimated beams. In embodiments where separating element 106 dividesthe light beam 105 into more than two collimated beams, the number ofREMA matches a number of collimated light beams. In some embodiments,beam separating element 106 includes a rotatable minor to change apropagation direction of the light beam 105. In some embodiments, beamseparating element 106 includes a piezoelectric lens that turns on oroff based on a control voltage. In some embodiments, the beam separatingelement 106 includes a prism.

Masks 108 a and 108 b are positioned to receive light 109 a and 109 bpassing through the slit of REMAs 102 a and 102 b, respectively. Masks108 a and 108 b each include a pattern corresponding to features to betransferred to wafer 116. In some embodiments, mask 108 a has adifferent pattern from mask 108 b. In some embodiments, mask 108 a hasthe same pattern as mask 108 b. In some embodiments where mask 108 a isdifferent from mask 108 b, the combined features transferred to thewafer from masks 108 a and 108 b include features having spacing belowthe resolution capabilities of a single mask.

Reflective elements 110 a and 110 b reflect light 111 a and 111 btransmitted by masks 108 a and 108 b, respectively, toward lightredirecting element 112. In some embodiments, reflective elements 110 aand 110 b are minors. In some embodiments, reflective elements 110 a and110 b are prisms. In some embodiments, reflective elements 110 a and 110b are wavelength selective. Wavelength selective reflective elements 110a and 110 b limit stray light of different wavelengths from enteringinto the lithography apparatus 100 and adversely impacting the transferof the patterns from masks 108 a and 108 b to wafer 116.

Light redirecting element 112 receives the light 113 a and 113 breflected by reflective elements 110 a and 110 b and redirects the light115 to projection lens 114. In some embodiments, light redirectingelement 112 is a mirror. In some embodiments, light redirecting element112 is a prism. In some embodiments, light redirecting element 112 iswavelength selective.

Projection lens 114 receives light 115 redirected by light redirectingelement 112 and focuses the light 117 onto wafer 116. Projection lens114 reduces the size of the pattern imparted into the light 115 by masks108 a and 108 b. In some embodiments, projection lens 114 reduces thesize of the pattern to a size three to seven times smaller than thepattern imparted into the light 115 by masks 108 a and 108 b. In someembodiments, projection lens 114 is a catoptric arrangement. In someembodiments, projection lens 114 is a catadioptric arrangement. In someembodiments, projection lens 114 includes aberration correctingelements. In some embodiments, projection lens 114 includes wavelengthselective elements. In some embodiments where light source 104 emits anultraviolet light beam, projection lens 114 includes refractive elementscomprising calcium fluoride. In some embodiments, projection lens 114has a numerical aperture ranging from 0.6 to 1.35. In some embodiments,projection lens 114 has a focal length ranging from 50 nm to 500 nm.

In some embodiments, wafer 116 is a semiconductor wafer. In someembodiments, wafer 116 is silicon, germanium, gallium nitride, or othersuitable material. In some embodiments, wafer 116 has a photoresistlayer formed over a surface of the wafer so that light 117 fromprojection lens 114 is incident upon the photoresist layer. When aphotoresist layer is present on wafer 116, the photoresist layer ispatterned by light transmitted through projection lens 114. In someembodiments, the photoresist layer is a positive photoresist material.In some embodiments, the photoresist layer is a negative photoresistmaterial.

Movable stage 118 supports wafer 116. Movable stage 118 is capable oftranslational movement in a plane perpendicular to the direction of thelight incident on wafer 116. Movable stage 118 translates wafer 116 sothat light from projection lens 114 is incident upon the desiredposition of the wafer. In some embodiments, movable stage 118 is movableusing a stepper motor. In some embodiments, movable stage 118 is movableusing a scanning motor. In some embodiments, movable stage 118 comprisesa rack and pinion arrangement. In some embodiments, movable stage 118 isdriven by a threaded screw arrangement. During the patterning process,movable stage 118 translates wafer 116 in a direction opposite to themovement direction of the slit of reticle masking elements 102 a and 102b. By moving wafer 116 in a direction opposite to the slit, thepatterning time for each position on the wafer is reduced. In addition,the size of the REMAs 102 a and 102 b is reduced because the range ofmotion for the slit is decreased because of the ability to concurrentlymove wafer 116.

The space 120 between wafer 116 and the proximate end of projection lens114 is filled with immersion liquid 122. Immersion liquid 122 has arefractive index substantially equal to the refractive index of a lastelement of projection lens 114 to reduce reflection and refraction at aninterface of the projection lens and the air. Reflection of light 117emitted from projection lens 114 reduces the intensity of light 117incident on wafer 116, which would increase a time to sufficientlypattern wafer 116 and energy consumption because light source 104 emitsa higher intensity light beam. In some embodiments, refraction of lightemitted from projection lens 114 causes the pattern transferred to wafer116 to have increased distortion because light is bent away from anintended direction. In some embodiments, immersion liquid 122 is water.In some embodiments, immersion liquid 122 is oil or other suitablematerial.

Lithography apparatus 100 facilitates double patterning of wafer 116.Double patterning is a technique used to transfer a desired design tothe wafer when features or spacing between features of the desireddesign are smaller than the resolution capabilities of a single mask. Insuch instances, the desired design is separated into multiple masks andthe pattern of each mask is separately transferred to the wafer. Whenmasks 108 a and 108 b have different patterns, lithography apparatus 100is used for double patterning. In some embodiments where the number ofcollimated beams emitted by beam separation element 106 and REMAs isgreater than two, lithography apparatus 100 is used for multiplepatterning more than two patterns onto wafer 116.

FIG. 2 is a diagram of a lithography apparatus 200 having dual REMAs 102a and 102 b. Similar to lithography apparatus 100, lithography apparatus200 includes light source 104, beam separation element 106, reflectiveelements 110 a and 110 b, light redirecting element 112, projection lens114, wafer 116, movable stage 118 and the space 120 between the waferand the projection lens is substantially filled with immersion liquid122. Unlike lithography apparatus 100, lithography apparatus 200includes a single mask 108′ in place of masks 108 a and 108 b.

Mask 108′ is positioned to be contacted by light 113 c redirected bylight redirecting element 112. Mask 108′ includes a pattern designcorresponding to features to be transferred to wafer 116. In someembodiments, only a single mask is used to pattern wafer 116.Lithography apparatus 200 uses mask 108′ in place of masks 108 a and 108b to reduce production cost associated with producing an additionalmask. Lithography apparatus 200 has an increased patterning speed incomparison to a conventional lithography apparatus having only a singleREMA.

FIG. 3 is a flow chart of a method 300 of patterning a wafer usinglithography apparatus 100 (FIG. 1). In operation 302, a position of theslits of REMAs 102 a and 102 b are set to the first position. The firstposition is outside the portion of REMAs 102 a and 102 b contacted byincident light from beam separation element 106 to prevent unintentionalpatterning of wafer 116.

In operation 304, wafer 116 is positioned by movable stage 118 so that afirst region of wafer 116 is patterned by the light transmitted by REMA102 a or 102 b and mask 108 a or 108 b. One of ordinary skill willrecognize, in some embodiments, operations 302 and 304 are reversed.

In operation 306, the pattern of mask 108 a is transferred to wafer 116by transmitting light through the slit of REMA 102 a while the slitmoves from the first position to a second position and wafer 116 movesin the opposite direction from the slit movement. The second position ison the opposite side of the light received from beam separation element106. For example, the first position is outside the incident lightreceived from beam separation element 106, the second position isoutside the incident light on an opposite side of the incident lightreceived from the beam separation element.

The movement of the slit has four phases. FIG. 4 is a graph of avelocity of the slit versus time. A first phase 402 is a speed up phase,where the slit accelerates from rest at the first position to a targetvelocity ranging from 400 mm/s to 700 mm/s. A second phase 404 is asettling phase, where the velocity of the slit transitions fromaccelerating to the target velocity. A third phase 406 is a constantvelocity phase, where the slit travels at the target velocity. A fourthphase 408 is a slow down phase, where the slit slows from the targetvelocity to rest at the second position. In order to accurately transferthe pattern of mask 108 a to wafer 116, patterning occurs during thirdphase 406.

Upon completion of operation 306, the pattern of mask 108 a istransferred to wafer 116. FIG. 5 is a diagram 500 of a scanning path 502for a patterning process. Regions 504 and 506 correspond to locations onwafer 116 which are patterned. Letters “A” and “B” in regions 504 and506 signify which pattern is transferred to a specific region. Forexample, the letter “A” in region 504 signifies the pattern of mask 108a is transferred to region 504, while the letter “B” in region 506signifies the pattern of mask 108 b is transferred to region 506.Following operation 306, region 504 includes the pattern of mask 108 aand region 506 is not patterned.

Returning to method 300, following the transfer of the pattern of mask108 a to wafer 116, the pattern of mask 108 b is transferred to wafer116 by transmitting light through the slit of REMA 102 b while the slitmoves from the first position to a second position while wafer 116continues to move in the opposite direction from the slit movement, inoperation 308. Also during operation 308 the slit of REMA 102 a isreturned to the first position. In some embodiments, a shutter is usedto block light along an optical path of REMA 102 a during the process ofthe slit returning to the first position. The shutter preventsunintentional patterning of wafer 116. In some embodiments, the shutteris positioned at an outlet of beam separating element 106. In someembodiments, the shutter is positioned in REMA 102 a. In someembodiments, the shutter is a separate element disposed along theoptical path of REMA 102 a.

Similar to operation 306, patterning of wafer 116 occurs during thethird phase 406 of the movement the slit of REMA 102 b. Followingoperation 306, region 504 includes the pattern of mask 108 a and region506 includes the pattern of mask 108 b. In embodiments where masks 108 aand 108 b have the same pattern, regions 504 and 506 will have the samepattern.

In some embodiments, the slit of REMA 102 b begins moving prior tocompletion of the patterning of region 504 (FIG. 5). By beginning themovement of the slit of REMA 102 b prior to the completion of patterningof region 504, the slit of REMA 102 b reaches constant velocityconcurrently with the completion of patterning of region 504. Thisarrangement avoids delaying the patterning of region 506 while the slitof REMA 102 b reaches the target velocity.

One of ordinary skill will recognize, in some embodiments, the order ofpatterning using REMAs 102 a and 102 b is reversed. In some embodiments,wafer 116 is first patterned using REMA 102 a and mask 108 a such thatregion 504 (FIG. 5) has the pattern of mask 108 a. In some embodiments,wafer 116 is first patterned using REMA 102 b and mask 108 b such thatregion 504 has the pattern of mask 108 b.

In operation 310, remaining regions of a first scan line of wafer 116are patterned. The patterning process is repeated in alternating fashionfor each region along the first scan line of wafer 116. Each region ispatterned using a different REMA 102 a or 102 b and mask 108 a or 108 bcombination than a previous region. Diagram 500 (FIG. 5) depicts thatthe first scan line includes seven regions and each region has thepattern of a different mask 108 a or 108 b from the previous region. Insome embodiments, the first scan line includes more than seven regions.In some embodiments, the first scan line includes less than sevenregions. Diagram 500 depicts the first scan line as a column. In someembodiments, the first scan line is a row. In some embodiments, thefirst scan line is any series of continuously patterned regions. Duringthe patterning of each region, the slit of REMA 102 a or 102 b notcurrently patterning wafer 116 is returned from the second position tothe first position and prepared for patterning a next region. A shutteris positioned to block light propagating through REMA 102 b during theprocess of returning the slit of REMA 102 b to the first position. Insome embodiments, the shutter is positioned at an outlet of beamseparating element 106. In some embodiments, the shutter is positionedin REMA 102 b. In some embodiments, the shutter is a separate elementdisposed along an optical path of REMA 102 b.

In operation 312, the slits of REMAs 102 a and 102 b (FIG. 1) are set tothe second position to prepare to pattern a second scan line. Diagram500 (FIG. 5) depicts scanning path 502 as an S-shaped path. To patternthe second scan line, the movement direction of the slits of REMAs 102 aand 102 b as well as wafer 116 are reversed. When patterning the secondscan line, the slits of REMAs 102 a and 102 b move from the secondposition to the first position and wafer 116 moves in the oppositedirection with respect to the movement of the slits, i.e., wafer 116moves in a reverse direction from the movement direction duringpatterning of the first scan line. In contrast to the patterning of thefirst scan line, the slits of REMAs 102 a and 102 b return to the secondposition following the transfer of the pattern of mask 108 a or 108 b towafer 116 during patterning of the second scan line.

In operation 314, the second scan line is patterned. The second scanline is patterned in a manner similar to the patterning of the firstscan line except the movement directions are reversed. For example,while REMA 102 a acts to transfer the pattern of mask 108 a to a regionof wafer 116, the slit of REMA 102 b returns to the second positionwhile wafer 116 continues to move in the opposite direction from theslits.

In operation 316, the remaining scan lines are patterned. The movementdirections for the slits of REMAs 102 a and 102 b as well as wafer 116are reversed for the patterning of each subsequent scan line. Diagram500 (FIG. 5) depicts four scan lines. In the embodiment of diagram 500,the direction of movement for the slits of REMAs 102 a and 102 b as wellas wafer 116 during the patterning of the first scan line are the sameas during the patterning of a third scan line. Similarly in theembodiment of diagram 500, the direction of movement for the slits ofREMAs 102 a and 102 b as well as wafer 116 during the patterning of thesecond scan line are the same as during the patterning of a fourth scanline. Diagram 500 depicts each scan line having the same number ofregions. In some embodiments, scan lines have a different number ofregions. In some embodiments where a wafer is circular in shape, thescan lines near a perimeter of the wafer have fewer regions than scanlines in a central portion of the wafer.

In optional operation 318, a second patterning process is performed onwafer 116. In the second patterning process, the opposite REMA and maskcombination from the first patterning process are used. For example,region 504 (FIG. 5) is patterned by REMA 102 b and mask 108 b during thesecond patterning process. Following optional operation 318, each regionof wafer 116 includes the pattern of mask 108 a and mask 108 b. Thus,method 300 performs double patterning on wafer 116. In some embodimentswhere the number of REMA and collimated beams is greater than two, morethan two patterning processes are performed to transfer more than twopatterns to wafer 116.

While method 300 is described in relation to lithography apparatus 100,one of ordinary skill will recognize the operations in method 300 arealso applicable to lithography apparatus 200. A wafer patterned bylithography apparatus 200 operating by method 300 will have the samepattern in each region of the wafer.

In addition to double patterning wafer 116, method 300 reduces undesiredeffects of particles on wafer 116. In some instances, particles orbubbles are formed during a manufacturing process. If the particlesremain in immersion liquid 122, the particles can prevent patterningillumination from contacting wafer 116. In previous techniques havingshort scan lines, the particles are trapped between projection lens 114and wafer 116. If the particles are close to wafer 116, the particlesblock light which prevents accurate patterning of wafer 116. If theparticles are suspended in immersion liquid 122 the particles scatterincident light which decreases the precision of the pattern transferredto wafer 116. By using longer scan lines, in comparison to previoustechniques, the particles are effectively swept away from projectionlens 114 and wafer 116 by the movement of movable stage 118. Thus, thelonger scan lines increase the precision of the pattern transferred towafer 116 by reducing the impact of the particles on the patterningprocess.

In conventional arrangements having only one REMA, the lithographicarrangement reverses movement directions for a slit of the single REMAand a wafer after patterning each region. This reversal limits theconventional arrangement to scan lines have a single region. The singleregion scan line results in a build up of particles in an immersionliquid which increases the risk of particles blocking patterningillumination or adhering to the wafer.

Method 300 enables longer scan lines than the conventional arrangement,which reduces the concentration build up of particles in the immersionliquid. The reduced concentration build up decreases the risk ofparticles blocking patterning illumination or adhering to the wafer.

Method 300 also increases the production speed versus conventionalarrangements. As discussed above, to precisely transfer the pattern ofmasks 108 a and 108 b to wafer 116, the patterning occurs during aconstant velocity phase of the slit movement. In the conventionalarrangement, the patterning process must be stopped between thepatterning of each region. For example, for a slit moving from a firstposition to a second position in a conventional arrangement, thepatterning process is stopped while the slit slows to a stop at thesecond position. The patterning process remains stopped while the slitspeeds up from the second position and settles to the target velocityfor patterning a subsequent region. Additionally, the patterning processis delayed by the time to move the wafer between scan lines. Because thescan line of the conventional arrangement includes only a single region,a number of scan lines in a conventional arrangement is significantlyhigher than a number of scan lines of method 300.

Conversely, method 300 is capable of patterning several regions withoutstopping the patterning process. By using two separate REMAs, method 300is able to pattern a region of the wafer by using one REMA while theother REMA reaches a constant velocity in preparation for patterning asubsequent region of the wafer. The reduced number of scan lines becauseof the ability to switch between REMAs and to reset a position of theslit of one REMA while the other REMA is patterning the wafer alsodecreases the total amount of delay in the patterning process necessaryto adjust the wafer position to subsequent scan lines.

One aspect of this description relates to a lithography apparatusincluding a light source configured to emit a light beam having awavelength, a beam separating element configured to divide the lightbeam into more than one collimated light beam, at least two REMA, whereeach REMA is positioned to receive one of the more than one collimatinglight beams, and each REMA comprises a movable slit for passing the onecollimated light beam therethrough, at least one mask having a pattern,wherein the at least one mask is configured to receive light from atleast one of the REMA and a projection lens configured to receive lightfrom the at least one mask.

Another aspect of this description relates to a method of patterning awafer including emitting a light beam having a wavelength from a lightsource, dividing the light beam into more than one collimate light beamsusing a beam separating element, transmitting each of the more than onecollimated light beams through a REMA such that a number of the morethan one collimated light beams is the same as a number of REMA, whereeach REMA includes a movable slit, forming a patterned light beam bypassing the more than one collimated light beam through at least onemask, reducing a size of the patterned light beam using a projectionlens, where the projection lens emits a reduced patterned light beam,patterning a first region of the wafer using the reduced patterned lightbeam, and moving the wafer following the patterning of the first regionusing a movable stage, where the movable stage supports the wafer.

It will be readily seen by one of ordinary skill in the art that thedisclosed embodiments fulfill one or more of the advantages set forthabove. After reading the foregoing specification, one of ordinary skillwill be able to affect various changes, substitutions of equivalents andvarious other embodiments as broadly disclosed herein. It is thereforeintended that the protection granted hereon be limited only by thedefinition contained in the appended claims and equivalents thereof.

What is claimed is:
 1. A lithography apparatus comprising: a beamseparating element configured to divide a light beam from a light sourceinto more than one collimated light beams; at least two reticle edgemasking assemblies (REMAs), wherein each REMA is positioned to receiveone of the more than one collimated light beams, and each REMA comprisesa movable slit for passing the one collimated light beam therethrough;at least one mask having a pattern, wherein the at least one mask isconfigured to receive light from at least one of the REMAs; and aprojection lens configured to receive light transmitted by the at leastone mask.
 2. The lithography apparatus of claim 1, wherein the at leastone mask is at least two masks and each mask receives light from one ofthe at least two REMAs.
 3. The lithography apparatus of claim 2, whereinthe at least two masks is at least one mask having a different patternthan at least another mask.
 4. The lithography apparatus of claim 2,wherein each mask of the at least two masks have the same pattern. 5.The lithography apparatus of claim 1, wherein the at least one mask isone mask and the mask receives light from all of the at least two REMAs.6. The lithography apparatus of claim 1, wherein the movable slitconfigured to move at a speed ranging from 400 mm/s to 700 mm/s.
 7. Thelithography apparatus of claim 1, further comprising: a movable stagesupporting a wafer.
 8. The lithography apparatus of claim 7, furthercomprising: an immersion liquid disposed between the wafer and theprojection lens.
 9. The lithography apparatus of claim 1, wherein thewavelength of the light beam is in an ultraviolet region of theelectromagnetic spectrum.
 10. The lithography apparatus of claim 1,wherein the projection lens is configured to reduce a size of thepattern of the at least one mask.
 11. A method of patterning a wafercomprising: emitting a light beam having a wavelength from a lightsource; dividing the light beam into more than one collimated lightbeams using a beam separating element; transmitting each of the morethan one collimated light beams through a reticle edge masking assembly(REMA) such that a number of the more than one collimated light beams isthe same as a number of REMA; forming a patterned light beam by passingthe more than one collimated light beam through at least one mask;reducing a size of the patterned light beam using a projection lens,wherein the projection lens emits a reduced patterned light beam;patterning a first region of the wafer using the reduced patterned lightbeam; and moving the wafer following the patterning of the first regionusing a movable stage, wherein the movable stage supports the wafer. 12.The method of claim 11, wherein patterning the first region of the wafercomprises moving the movable slit of a first REMA in a first directionand moving the wafer in a second direction, the second direction beingopposite the first direction.
 13. The method of claim 12, whereinpatterning the first region of the wafer comprises moving the movableslit of a second REMA to a first position.
 14. The method of claim 12,further comprising: patterning a second region of the wafer using thereduced patterned light beam, wherein the reduced patterned light beamfor patterning the first region of the wafer is transmitted from thefirst REMA and the reduced patterned light beam for patterning thesecond region of the wafer is transmitted through a second REMA.
 15. Themethod of claim 14, wherein patterning the second region of the wafercomprises moving the movable slit of the first REMA to a first positionby moving the movable slit in the second direction.
 16. The method ofclaim 14, wherein patterning the second region of the wafer comprisesmoving the movable slit of the second REMA in the first direction andmoving the wafer in the second direction.
 17. The method of claim 11,wherein forming a patterned light beam comprises transmitting one of themore than one collimated light beams through a first mask, andtransmitting another of the more than one collimated light beams througha second mask, and the first mask and the second mask have a samepattern.
 18. The method of claim 11, wherein forming a patterned lightbeam comprises transmitting one of the more than one collimated lightbeams through a first mask, and transmitting another of the more thanone collimated light beams through a second mask, and the first mask andthe second mask have different patterns.
 19. The method of claim 11,wherein forming a patterned light beam comprises transmitting all of themore than one collimated light beams through a single mask.
 20. Themethod of claim 11, wherein patterning the first region of the wafercomprises transmitting the reduced patterned light beam through animmersion liquid.